Lawmakers and community leaders from Montgomery and Prince George’s counties planned to join University of Maryland officials Tuesday evening to call for state funding of a proposed 16-mile Purple Line.

Purple Line supporters said they would ask the General Assembly to raise the state gas tax and dedicate some of that revenue to designing and building a Purple Line light rail link between Bethesda and New Carrollton via Silver Spring and College Park. The Maryland Transit Administration estimates construction would cost $1.93 billion.

State officials have said they need to split the costs with the federal government. The Federal Transit Administration recently approved the project for preliminary engineering, but no funding is in place.

Ralph Bennett, president of Purple Line NOW, said his group will urge the General Assembly to support a gas tax increase only if some of the revenue is earmarked for a Purple Line.

“It’s clear the funding we have to spend on transportation is way behind the needs,” Bennett said.

A news conference was scheduled for 6 p.m. at the Stamp Student Union on the University of Maryland’s College Park campus, outside an MTA open house about the state’s Purple Line plans.

The next open house on the Purple Line proposal is scheduled for Wednesday, 5:30 to 8:30 p.m. at the National 4-H Youth Conference Center, 7100 Connecticut Ave., Chevy Chase. An open house is also scheduled for Monday from 5:30 to 8:30 p.m. at the Silver Spring Civic Building, 1 Veterans Place.